Burglar alarm



March 16 1926. v 1,576,818

B. FOTHERINGHAM BURGLAR ALARM Filed .July 22 1925 F291. ZIT?? Patented Mar. 16, 1926.

BRUCE FOTHERINGI-IAM, OF ONTARIO, CALIFORNIA.

BURGLAR ALARM.

Application 'filed July 22, 1925. Serial No. 45,226.

T0 all whom t may concern Be it known that I, BRUCE FOTHERING- HAM, a citizen of the United States, residing at Ontario, in the county of San Bernardino and State of California7 have invented new and useful Improvements in Burglar Alarms, of which the following is a specification.

My invention is a burglar alarm of the explosive type adapted to discharge a blank cartridge on the opening of a door, gate or the like. My invention is particularly adapted for use in a farm enclosure for stock or the like or for apoultry house in which an authorized person may set the gun from the inside of the enclosure or the poultry house, close the gate or door and release the latch of the gun so that it will be set to explode on the opening of the gate or the door.

My invention in its various details comprises a gun having a fixed cartridge holder and a heavy spring actuated hammer which is maintained in an elevated position with the springs tensioned by a spring pressed arm, the latter being movable on the opening of the door to release the hammer. I also provide a latch so that the hammer may be held in a safety position after loading the gun' on the inside of the yard or poultry house and the latch may be released from the outside to allow the hammer to come into engagement with a pivoted arm or trig- 0fer.

My invention will' be more readily understood from the following description and drawings in which;

Figure 1 is an elevation of my burglar alarm gun showingl the hammer elevated in its latched position in what may be considered a safety lock.

Fig. 2 is an elevation similar to Fig. 1, showing the hammer engagingthe swivelling trigger arm and in a position for exploding the cartridge on the opening of the gate or door.

Fig. 3 is a view similar to Figs. 1 and 2, showing the hammer dropped, exploding the cartridge on the opening of the gate or door. Y

Fig. 4 is a horizontal cross section on the line 4-4 of Fig. 2.

Fig. 5 is a horizontal section on the-line 5-5 of Fig. 3.

ving of such internal -Fig; 6 is a vertical section on the line 6*(3 of Fig. 2 in the direction of the arrows.

In the drawings 1 indicates a fixed part of a fence or the interior wall of a building such as a post or a doorfrarneV of a building and 2 designates a fence gate or a building door being hinged by the hinges 3 to the post or door frame. VMy alarm gun signal is adapted to be actuated on the unauthorized opening of the gate or door.

The signal comprises a bracket 4 having a gun barrel 5 formed of a section of tubdiameter as to hold the cartridge shell 6 and `engage the rim 7 thereof. 'Ihe bracket is secured to the post in any suitable manner and forms a stationary mounting for the gun barrel or tube. The hammer 8 consists of a heavy bar of metal 9 having a cylindrical bore 10 at its lower end adapted to slide on the outside of the barrel 5 and having a projection 11 to engage the explosive cap of the usual cartridge. The hammer is provided with a latch slot 12 in onev side for a purpose to be hereafter described. The upper end of the hammer bar has a stern 13 preferably of reduced diameter, with an elongated notch 14, cut in one side. This notch has a squared shoulder 15, an inclined shoulder 16 and an inclined tip 17.

A yoke 18 extends across the hammer bar and is connected thereto by means of a lflot 19 in the yoke engaging around a rivet 20 secured to the hammer bar. A pairof tension springs 21 are secured to the yoke and at their lower ends are fastened by hooks 22 to the bracket 4. These springs func tion to draw the hammer bar downwardly with considerable force to explode the cartridge so that the action is practically independent of the drop of the hammer by gravity after being tripped as hereafter explained.

The trigger arm 23 consists of a metal rod p'ivotally connected to the upper end of the bracket 4 by means of a swivel pin 24. The outer end 25 of the trigger arm is adapted to beary against the door 2. A tension spring 26 is positioned between the arm and the post 1 to hold the arm tightly pressed against the door. The arm engages in the notch 14 engaging the shoulder 15 to hold the hammer in set position.

The latch which also forms a safety device is designated generally by the numeral 27 and comprises a latch bar 28 sliding in a socket 29 and be operated by a key 3() engaging the latch bolt to retract it or to project it into engagement with the latch slot 12. The key is removable from the latch at the outside and a knob 31 is provided on the inside so as to operate the latch. The latch shown is of a type which remains-in the position in which it is moved "by the 'key or the knob.

The manner of loading the gun is as folylows:

The yoke 18 is vlifted off therivet 2O so that the hammer may be completely removed from the barrel 5. A 'cartridge is then inserted and the han-nner replaced, the yoke 'being secured in its normal position.

The hammer will then be raised vuntil the latch bar 28 is opposite the latch slot 12 when the latch bar is moved into engagement therewith througl'i the medium of the knob "31. This setting` `=of the gun in the safety latchposit-ion is done by an authorized party jfrom the interior of the building or the enclosed yard.

"When `the gate is lswung closed by the ope '-a'tor passing out therethrough, `the trigger farms'win-gs from the position shown in Fig. 5 ito Athat of Fig. l so that it fits within the slotor notch 14 in the stem 13 of the hammer bar. lV'hen the operator -is on the outside of the building or the enclosure, he opera-tes ithe v4latch bar 28 iby means of the key 30 to withldraw the bar from the slot 12 and thereby sets ythe gun inoperative position.

The discharge of the gun is caused by the iopening ofthe gate `in which action a trig- Igen'arm 23 'is lpressed outwardly from the position shown in Fig. 4 to that of Fig. 5 andso releases the engagement of the arm jand the shoulder'l vof the stem, allowing the hammer t'o drop and' explode the cartridge. As above described the tension springs 21 "draw the hammer downwardly with considierable'force, thereby making the device ifndependent 'of gravity.

lThe Jgirn 'and `hammer with the other def tail'fparts "of the mechanism may be placed in idifferent positions if desiredv and may be 'arrangedltodischarge vertically as the L.tiring 'actiorrisv 'mainly caused 'by the springs.

After the operator has set the gunv to discharge -for instance in the evening, he may "s'et it ein' the 'safety position, for instance in ithe morning vbyV utilizing t-he key to throw the Elatch bar into 'engagement with 'the latch slot 12 fand 'thus lock Ethe hammer bar against 'rin'g He may then open the `gate or door Vand pass -m and out freely. Tit-h the c'onstruction shown it is' not necessary to yunload the gun, as this is '-a simple matter' it may lbe quickly accomplished ori if desired the hammer may be manually lowered into the posiconsiderably modified to suit special requirements,

different ways of mounting and so forth. @ther types of latches may be used or they may be discarded if a person merely wants a simple device, in which case the gun could be set from the outside of the yard or building by the operator passing a loop wire through an aperture 32 in the gate above the hammer, the loop being designed to engage either the rivet 2() or the shoulder 15.

Having described my invention, what I claim is:

1. A burglar alarm comprising in combination 'a barrel adapted to hold and retain a cartridge, a hammer bar having a cylindrical bore, said here bei-ng adapted to slide over 'the barrel and having a `'notch at its upper end, a Vtrigger arm'adaptcd to engage in the notch, said trigger arm being adapted to swivel to release the hammer bar and allow vthe hammer to drop to strike and explode the cartridge.

2. A burg-lar alarm comprising in combination a bracket adapted to be secured to a gate post, a tubular barrel secured thereto adapted to hold a cartridge with its rim on the upper end of the barrel, a hammer bar having a cylindrical bore in its lower end, -said bore -being slidahlc -over the barrel, an -ufpwardly extending 4stem connected to the Ahammer bar and havinga notch therein with a squaredshoulder, a triggerarm pivoted to the brac tet Ato swing horizontally, a spring to draw `the Vtrigger Iarm towards the post, 'said ytrigger armlmvfing its outer end shaped and vpositioned to engage va gate and to engage the said shculdcr whereby on opening the gate the trigger Iarm is swivelled out of engagement with ythe shoulder to allow the hammer to drop and explode the cartridge.

3. A burglar alarm comprising in combination labbracket ladapted to be secured to a gate post, -a tubularbarrel 'secured' thereto, adapted to hold a cartridge with its rim on the rripper end of the barrel, a hammer bar having a cylindrical bore at its lower end,

lsaid 'bore lbeing slidable over the barrel, an

upwardly extending 'stem connected to the hammer bar, having `a notch therein, a triggerfarm pivoted tothe bracket to swing horiyokeon the llatch bar engaging the rivet. and

tension springs between the yoke and the flower [portion of the Ibracket.

In testimony whereof l have signed my lnfame to 'this specification.

BRUCE FOTHERINGHAM. 

